This invention relates to the field of ball feeding methods and apparatus in general, and more specifically to a method and apparatus for use with balls of a substantially uniform diameter for providing a continuous, rapid flow of said balls.
One of the limiting factors in the speed of manufacturing systems using very large quantities of balls has been the rate with which those balls can be organized and fed from a massive quantity into a continuous, serially flowing stream of individual balls. The problems encountered with ball feeding systems becomes especially acute in the case of small, high tolerance balls, as used in ballpoint pens, which are prone to jamming and burring in conventional feeding apparatus. Such feeding systems suffer from a substantial amount of "down time" spent while freeing jammed balls from the feeder mechanism, as well as a substantial number of reject balls whose surfaces are unacceptably burred or flattened while being handled by the feeder
Prior art ball feeders primarily comprise the "gum ball" type of feeder, in which a metal disc is rotated at the bottom, or base, of a hollow cylinder filled with balls. Holes or radial slots are bored through the disc, forming an open topped enclosure between the walls of the moving hole or slot and the fixed base of the cylinder upon which the disc rotates. The balls at the bottom of the cylinder fall into these enclosures and are carried by the rotating disc until the hole (or slot) overlies an exit hole in the base of the cylinder. The balls then fall from the rotating disc into the hole in the cylinder base and are fed to a desired location by ramps or tubes.
One of the major disadvantages of gum ball-type feeders results from the scissoring action between a hole in the cylinder base and a corresponding hole in the disc, as the latter rotates out of alignment with the former. Especially in the case of small balls, this scissoring action may catch a ball halfway between the disc and the base and either burr the surface of the ball or jam it in between the disc and the cylinder base.
A further disadvantage, especially with balls made of soft material such as silver or indium, lies in the fact that after a hole or slot in the disc has been filled, the tops of the enclosed balls moving with the disc form a rough surface which moves past the stationary balls above the disc and causes flat spots on both the moving and stationary balls. This effect is accentuated by the fact that the stationary bottom layer of balls are not isolated from the pressure of the mass of balls above the bottom layer, and thus are squeezed between the tops of the enclosed, moving balls and the mass of balls above them as the disc rotates.
In order to minimize the down time and damage caused by the above described problems with conventional gum ball feeders, the feeders must be operated at a relatively slow rate of speed, thus limiting the speed with which a manufacturing process can be carried out.
It is therefore an object of the present invention to provide a high speed system for feeding a mass or load of balls to an external apparatus in a serial array, with a minimum of down time and ball damage.